Refrigerant circulation device and control method

Abstract

A refrigerant circulation device according to the present disclosure comprises: a common flow path through which a primary refrigerant flows; a first flow path and a second flow path branched from the common flow path; a third flow path through which a secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass and which exchanges heat between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path; a second valve that adjusts the flow rate of the primary refrigerant in the second flow path; a sensor unit that detects a secondary temperature, which is the temperature of the secondary refrigerant, a device temperature, which is the temperature inside the device, and a relative humidity inside the device; and a changing unit that changes a first opening degree, which is the opening degree of the first valve, and a second opening degree, which is the opening degree of the second valve, on the basis of the secondary temperature, the device temperature, and the relative humidity such that the sum of the first opening degree and the second opening degree becomes a prescribed value.

Description

Technical Field

[0001] The present disclosure relates to a refrigerant cycle device and a control method. Background Art

[0002] In the refrigerant cycle device as the background art, the inflow amount of the primary refrigerant flowing into the exchanger is controlled so that the dew point in the refrigerant cycle device is not lower than the temperature of the secondary refrigerant (hereinafter also referred to as "secondary temperature"). Specifically, the opening degree of the valve provided in the flow path of the primary refrigerant is adjusted so that the secondary temperature is maintained within the range of dew point + 1°C to dew point + 1.5°C (for example, refer to Patent Document 1). Prior Art Documents Patent Documents

[0003] Patent Document 1: Specification of Chinese Patent No. 103115514 Summary of the Invention Technical Problem to be Solved by the Invention

[0004] In the refrigerant cycle device of the background art, in order to suppress condensation, the opening degree of the valve provided in the flow path of the primary refrigerant is adjusted so that the secondary temperature falls within the range of dew point + 1°C to dew point + 1.5°C. However, only by this adjustment, the valve opening degree may be relatively small. As a result, the pressure in the flow path of the primary refrigerant sometimes increases.

[0005] An object of the present disclosure is to provide a technique capable of suppressing condensation in a refrigerant cycle device and suppressing an increase in pressure in the flow path of the primary refrigerant. Technical Means for Solving the Technical Problem

[0006] The refrigerant cycle device according to one aspect of the present disclosure includes: a common flow path through which a primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which a secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass inside, and heat exchange is performed between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path; a second valve that adjusts the flow rate of the primary refrigerant in the second flow path; a sensor unit that detects a secondary temperature as the temperature of the secondary refrigerant, a device temperature as the temperature inside the device, and the relative humidity inside the device; and a change unit that changes a first opening degree as the opening degree of the first valve and a second opening degree as the opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first opening degree and the second opening degree becomes a specified value.

[0007] Another refrigerant cycle device according to an aspect of the present disclosure includes: a common flow path through which a primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which a secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass inside, and heat exchange is performed between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path, i.e., a first flow rate; a second valve that adjusts the flow rate of the primary refrigerant in the second flow path, i.e., a second flow rate; a sensor unit that detects a secondary temperature as the temperature of the secondary refrigerant, a device temperature as the temperature inside the device, and a relative humidity inside the device; and a changing unit that changes a first opening degree as the opening degree of the first valve and a second opening degree as the opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity, such that the sum of the first flow rate and the second flow rate becomes a specified value.

[0008] Another control method according to an aspect of the present disclosure is a control method for a refrigerant cycle device, the refrigerant cycle device including: a common flow path through which a primary refrigerant flows; a first flow path and a second flow path branching from the common flow path; a third flow path through which a secondary refrigerant flows; a heat exchanger through which the first flow path and the third flow path pass inside, and heat exchange is performed between the primary refrigerant and the secondary refrigerant; a first valve that adjusts the flow rate of the primary refrigerant in the first flow path; and a second valve that adjusts the flow rate of the primary refrigerant in the second flow path, detecting a secondary temperature as the temperature of the secondary refrigerant, a device temperature as the temperature inside the device, and a relative humidity inside the device, and changing a first opening degree as the opening degree of the first valve and a second opening degree as the opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity, such that the sum of the first opening degree and the second opening degree becomes a specified value. Advantages of the Invention

[0009] According to the present disclosure, a technique can be provided that can suppress dew condensation in a refrigerant cycle device and can suppress a pressure increase in a flow path of a primary refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram showing the structure of the cooling system 100. Figure 2 is a block diagram of the CDU1 of the embodiment. Figure 3 is showing Figure 1Flow chart of the first part of the processing of the CDU1 shown Figure 4 Shows Figure 1 Flow chart of the second part of the processing of the CDU1 shown Figure 5 Shows Figure 1 Flow chart of the third part of the processing of the CDU1 shown Figure 6 Is a diagram showing the control content of each condition in the processing of the CDU1 Figure 7 Is a block diagram of the CDU1 of Modification 1 Figure 8 Is Figure 7 Flow chart of the processing of the CDU1 shown Figure 9 Is a flow chart showing the first part of the processing of the CDU1 of Modification 2 Figure 10 Is a flow chart showing the second part of the processing of the CDU1 of Modification 2 Figure 11 Is a flow chart showing the third part of the processing of the CDU1 of Modification 2 Figure 12 Is a diagram of the structure of the CDU1 of Modification 3 Detailed implementation mode

[0011] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated description will not be given

[0012] [Definition of terms] Hereinafter, the term "connection" means "fluidly connectable connection"

[0013] [Cooling system 100] As Figure 1 Shown, the cooling system 100 includes a refrigerant circulation device 1, a distribution manifold 2, a collection manifold 3, at least one cold plate 4, a cooling device 6, and flow paths 7 and 8 as components. Through these components, at least one heat source 5 provided in the space A01 is cooled

[0014] In addition, when the cooling system 100 includes one cold plate 4, the cooling system 100 may not include the distribution manifold 2 and the collection manifold 3

[0015] Furthermore, hereinafter, the refrigerant circulation device 1 will also be referred to as "CDU1" Among the components, the CDU1, the distribution manifold 2, the collection manifold 3, and the plurality of cold plates 4 are arranged in the space A01. The space A01 is, for example, a server room.

[0017] [Heat source 5, rack 9] The rack 9 is arranged in the space A01. A plurality of heat sources 5 are accommodated in the rack 9. Each heat source 5 is typically an electronic component or an electronic device. An electronic component is a component that constitutes an electronic device and includes, for example, a central processing unit (so-called CPU), an electrolytic capacitor, a power semiconductor module, or a printed circuit board. The electronic component operates by being powered and generates heat. An electronic device is a rack-mounted server or a blade server. In addition, the electronic device can also be a projector, a personal computer, or a display.

[0018] [Embodiment (CDU1)] The CDU1 can be circulated in the market as the cooling system 100. When circulated as the cooling system 100, the cooling device 6, the flow paths 7, 8 can be removed from the cooling system 100. The CDU1 can be circulated separately in the market. In the present embodiment, the CDU1 is, for example, accommodated in the rack 9 during use. However, it is not limited thereto, and the CDU1 can be arranged outside the rack 9 during use.

[0019] [Primary inlet 11, primary outlet 12, secondary inlet 13, secondary outlet 14] As Figure 1 shown, the CDU1 includes a primary inlet 11, a primary outlet 12, a secondary inlet 13, and a secondary outlet 14. The low-temperature primary refrigerant C1 flows into the primary inlet 11 through the flow path 7. The high-temperature secondary refrigerant C2 flows into the secondary inlet 13 from the collection manifold 3. The CDU1 performs heat exchange between the primary refrigerant C1 (low temperature) flowing into the CDU1 from the primary inlet 11 and the secondary refrigerant C2 (high temperature) flowing into the CDU1 from the secondary inlet 13. Thus, in the CDU1, the thermal energy of the primary refrigerant C1 moves to the secondary refrigerant C2. Specifically, the temperature of the secondary refrigerant C2 when flowing out of the CDU1 is lower than the temperature when flowing into the CDU1. The CDU1 transports the temperature-reduced secondary refrigerant C2 from the secondary outlet 14 to the distribution manifold 2. The CDU1 transports the temperature-increased primary refrigerant C1 from the primary outlet 12 to the flow path 8.

[0020] [Primary refrigerant C1, secondary refrigerant C2] The primary refrigerant C1 is a fluid such as a coolant. Examples of the coolant include antifreeze or pure water. Typical examples of the antifreeze are an ethylene glycol aqueous solution or a propylene glycol aqueous solution. The secondary refrigerant C2 is a fluid of the same type or a different type from the primary refrigerant C1. In addition, at least one of the primary refrigerant C1 and the secondary refrigerant C2 can be a gas refrigerant.

[0021] [Distribution Manifold 2] The distribution manifold 2 includes a common flow path 21 and a plurality of individual flow paths 22. Figure 1 In the figure, for the purpose of ease of understanding, only two individual flow paths 22 are shown. The fluid can circulate in the common flow path 21 and the individual flow paths 22. One end T21 of the common flow path 21 is connected to the secondary outflow port 14 and serves as an inflow port for the fluid in the distribution manifold 2. One end T22a of each individual flow path 22 is connected to the common flow path 21. The other end T22b of each individual flow path 22 serves as an outflow port for the secondary refrigerant C2 in the distribution manifold 2 and is respectively connected to the inflow port 41 of the cold plate 4. Therefore, the secondary refrigerant C2 (low temperature) flowing into the inflow port (i.e., one end T21) of the distribution manifold 2 first circulates in the common flow path 21, is divided into the individual flow paths 22, and then flows out from the individual outflow ports (i.e., the other end T22b) of the distribution manifold 2.

[0022] [Cold Plate 4] Each cold plate 4 is in thermal contact with at least one heat source 5. A secondary refrigerant C2 (low temperature) flows within each cold plate 4. Specifically, each cold plate 4 is configured to be in direct thermal contact with the heat source 5. Each cold plate 4 can be provided in thermal contact with the heat source 5, for example, via a heat conducting sheet (not shown). The term "thermal contact" encompasses both direct and indirect thermal contact.

[0023] Each cold plate 4 includes an inlet 41, an outlet 42, and an internal flow path 43 for the secondary refrigerant C2. The internal flow path 43 connects the inlet 41 and the outlet 42. The secondary refrigerant C2 (low temperature) flows into the inlet 41 from the separate flow path 22 connected to the inlet 41. The secondary refrigerant C2 circulates within the internal flow path 43 to the outlet 42. Therefore, the thermal energy generated in the heat source 5 is transferred to the secondary refrigerant C2 flowing in the internal flow path 43 of the cold plate 4, which is in thermal contact with the heat source 5. As a result, the heat source 5 is cooled, and the temperature of the secondary refrigerant C2 increases. The secondary refrigerant C2 (high temperature) flows out of the outlet 42 to the separate flow path 31 of the collection manifold 3.

[0024] [Collection Manifold 3] The collecting manifold 3 includes a plurality of individual flow paths 31 and a common flow path 32. Figure 1In this, for the purpose of easy understanding, two separate flow paths 31 are shown. Fluids can flow within each of the separate flow paths 31 and the common flow path 32. One end T31a of each separate flow path 31 is respectively connected to the fluid outlet 42, serving as the fluid inlet in the collection manifold 3. The other end T31b of each separate flow path 31 is connected to the common flow path 32. One end T32 of the common flow path 32 serves as the fluid outlet in the collection manifold 3 and is connected to the secondary fluid outlet 13. Therefore, the secondary refrigerant C2 flowing into each fluid inlet (i.e., one end T31a) in the collection manifold 3 from the cold plate 4 converges in the common flow path 32 and flows out from one end of the collection manifold (i.e., one end T32) to the secondary fluid inlet 13 of the CDU1. Therefore, the secondary refrigerant C2 circulates in the CDU1, the distribution manifold 2, the cold plate 4, and the collection manifold 3 in the order of the CDU1, the distribution manifold 2, the cold plate 4, and the collection manifold 3.

[0025] [Cooling device 6] The cooling device 6 is provided, for example, outside the space A01. Additionally, the cooling device 6 can be provided anywhere indoors or within the room. The cooling device 6 is, for example, a chiller or a cooling tower. The cooling device 6 includes an inlet 61, an outlet 62, an internal flow path 63, a cooling section 64, and a pump 65 for the primary refrigerant C1. The internal flow path 63 connects the inlet 61 and the outlet 62. Each of the cooling section 64 and the pump 65 is inserted into the internal flow path 63.

[0026] The primary refrigerant C1 flowing into the inlet 61 flows through the flow path into the cooling section 64. The cooling section 64 cools the primary refrigerant C1 flowing into the cooling section 64. The cooling method in the cooling section 64 can be any one of the air-cooling method or the water-cooling method. The primary refrigerant C1 flowing out of the cooling section 64 flows into the pump 65 through the internal flow path 63. The pump 65 pressurizes and transports the primary refrigerant C1 flowing into the pump 65 to the outlet 62. In Figure 1 this, the pump 65 is located between the cooling section 64 and the outlet 62 in the internal flow path 63. However, it is not limited to this, and the pump 65 can be located between the outlet 62 and the cooling section 64 in the internal flow path 63.

[0027] [Structure of the CDU1] As Figure 2 shown, the CDU1 includes a housing 15, a primary flow path 16, a secondary flow path 17, a heat exchanger 18, a sensor section 19, an operation section 110, and a control section 111.

[0028] [Housing 15] The housing 15 separates the internal space of the CDU1 from the external space of the CDU1. The housing 15 has a primary fluid inlet 11, a primary fluid outlet 12, a secondary fluid inlet 13, and a secondary fluid outlet 14.

[0029] [Primary flow path 16] The primary flow path 16 includes connectors 16a, 16b, valves 16c, 16d, pipes 16e to 16k, and a flow path 18e (described later) of the heat exchanger 18. The primary flow path 16 is installed within the housing 15. The primary flow path 16 is the piping for the primary refrigerant C1 in the CDU1.

[0030] Each of the connectors 16a, 16b is a so-called three-way connector. Specifically, each of the connectors 16a, 16b is in a T shape and has connection ports in three directions (i.e., a first connection port, a second connection port, and a third connection port). In the embodiment, each of the valves 16c, 16d is a two-way valve whose flow rate can be adjusted under the control of the control unit 111, and includes a valve box, a valve body, a valve seat, a first connection port, a second connection port, etc. The opening degree of the valves 16c, 16d (i.e., the valve seat) is adjusted under the control of the control unit 111.

[0031] The pipe 16e connects the primary flow inlet 11 and the first connection port of the connector 16a. The pipe 16f connects the second connection port of the connector 16a and the first connection port of the valve 16c. The pipe 16g connects the second connection port of the valve 16c and the flow inlet 18a of the heat exchanger 18. The pipe 16h connects the third connection port of the connector 16a and the first connection port of the valve 16d. The pipe 16i connects the second connection port of the valve 16d and the first connection port of the connector 16b. The pipe 16j connects the flow outlet 18b of the heat exchanger 18 and the second connection port of the connector 16b. The pipe 16k connects the third connection port of the connector 16b and the primary flow outlet 12.

[0032] The pipe 16e is an example of the "common flow path" of the present disclosure. The combination of the connector 16a, the pipe 16f, the valve 16c, the pipe 16g, the flow path 18e, the pipe 16j, and the connector 16b is an example of the "first flow path" of the present disclosure. The valve 16c is also an example of the "first valve" of the present disclosure, and adjusts the flow rate of the primary refrigerant C1 in the first flow path of the present disclosure.

[0033] The combination of the connector 16a, the pipe 16h, the valve 16d, the pipe 16i, and the connector 16b is an example of the "second flow path" of the present disclosure. The valve 16d is an example of the "second valve" of the present disclosure, and adjusts the flow rate of the secondary refrigerant C2 in the second flow path of the present disclosure.

[0034] When the opening degrees of the valves 16c, 16d are the same, the flow rate of the flow path from the connector 16a via the valve 16c to the connector 16b (i.e., the "first flow path" of the present disclosure) and the flow rate of the flow path from the connector 16a via the valve 16d to the connector 16b (i.e., the "second flow path" of the present disclosure) are the same. Thus, it is possible to easily change the first opening degree D1 and the second opening degree D2 by the change unit 111a described later.

[0035] [Secondary flow path 17] The secondary flow path 17 includes connectors 17a, 17b, pumps 17c, 17d, and pipes 17e to 17k. The secondary flow path 17 is installed within the housing 15. The secondary flow path 17 is the piping for the secondary refrigerant C2 in the CDU1. The secondary flow path 17 is an example of the "third flow path" of the present disclosure.

[0036] Similar to the connector 16a, each of the connectors 17a, 17b is, for example, a three-way connector. Each of the pumps 17c, 17d includes a housing, a pump rotor, an inlet, an outlet, etc. The pump rotor rotates within the housing by the driving force from the pump motor. As a result, each of the pumps 17c, 17d pressurizes and sends out the fluid flowing in from its own inlet from the outlet.

[0037] The pipe 17e connects the secondary inlet 13 and the inlet 18c of the heat exchanger 18. The pipe 17f connects the outlet 18d of the heat exchanger 18 and the first connection port of the connector 17a. The pipe 17g connects the second connection port of the connector 17a and the inlet of the pump 17c. The pipe 17h connects the outlet of the pump 17c and the first connection port of the connector 17b. The pipe 17i connects the third connection port of the connector 17a and the inlet of the pump 17d. The pipe 17j connects the outlet of the pump 17d and the second connection port of the connector 17b. The pipe 17k connects the third connection port of the connector 17b and the secondary outlet 14.

[0038] [Heat exchanger 18] The heat exchanger 18 is, for example, a plate heat exchanger. The heat exchanger 18 has a plurality of heat conducting plates stacked in the same direction (i.e., a stack of heat conducting plates), an inlet 18a and an outlet 18b for the primary refrigerant C1, and an inlet 18c and an outlet 18d for the secondary refrigerant C2. Each of the inlets 18a, 18c and the outlets 18b, 18d is located, for example, on a heat conducting plate at one end of the stack. In addition, a flow path 18e for the primary refrigerant C1 to flow from the inlet 18a to the outlet 18b is formed in the stack. In addition, a flow path 18f for the secondary refrigerant C2 to flow from the inlet 18c to the outlet 18d is formed in the stack.

[0039] The primary refrigerant C1 flows into the flow path 18e within the stack from the inlet 18a and flows within the stack toward the outlet 18b. The secondary refrigerant C2 flows into the flow path 18f within the stack from the inlet 18c and flows within the stack toward the outlet 18d. That is, the first flow path of the present disclosure and the third flow path of the present disclosure pass through the inside of the heat exchanger 18.

[0040] In addition, in the laminate of the heat conducting plates, the high-temperature secondary refrigerant C2 and the low-temperature primary refrigerant C1 flow in a physically isolated state. Each heat conducting plate is made of a material with relatively low heat conduction resistance. Therefore, in the laminate, heat exchange occurs between the primary refrigerant C1 (low temperature) and the secondary refrigerant C2, that is, the heat exchanger 18 exchanges heat between the primary refrigerant C1 and the secondary refrigerant C2. As a result of the heat exchange, the thermal energy of the secondary refrigerant C2 is transferred to the primary refrigerant C1. That is, the temperature of the secondary refrigerant C2 when flowing out from the outlet 18d is lower than the temperature when flowing into the inlet 18c.

[0041] [Sensor unit 19] The sensor unit 19 detects the secondary temperature T2o which is the temperature of the secondary refrigerant C2, the device temperature Td which is the temperature in the CDU1, and the relative humidity Hd inside the CDU1. Specifically, the sensor unit 19 includes temperature sensors 19a, 19b, and a humidity sensor 19c.

[0042] Specifically, the temperature sensor 19a detects the secondary temperature T2o between the outlet 18d in the secondary flow path 17 and the secondary outlet 14, and outputs the information indicating the secondary temperature T2o to the control unit 111. Specifically, the temperature sensor 19b detects the device temperature Td near the heat exchanger 18, and outputs the information indicating the device temperature Td to the control unit 111.

[0044] Specifically, the humidity sensor 19c detects the relative humidity Hd near the heat exchanger 18, and outputs the information indicating the relative humidity Td to the control unit 111.

[0045] Hereinafter, the information indicating the secondary temperature T2o, the device temperature Td, and the relative humidity Hd may sometimes be simply referred to as "secondary temperature T2o", "device temperature Td", and "relative humidity Hd", respectively.

[0012] In addition, the sensor unit 19 may be provided with a flow sensor in each of the pipes 16g, 16j. In addition to this, the sensor unit 19 may further include a pressure sensor.

[0046] [Operation unit 110] The CDU1 further includes an operation unit 110. The operation unit 110 is, for example, a touch screen. The touch screen includes a display and a touch sensor.

[0047] [Control unit 111] The control unit 111 includes electronic circuits such as a microcomputer and a memory (not shown). The control unit 111 is located above the primary flow path 16 and the secondary flow path 17 in the vertical direction of the housing 15 of the CDU1. Thus, even when the primary refrigerant C1 leaks from the primary flow path 16 or the secondary refrigerant C2 leaks from the secondary flow path 17, the electronic circuits will not be immersed in the leaked primary refrigerant C1 or secondary refrigerant C2.

[0048] The microcomputer controls the components of the CDU1 according to the programs stored in the memory. Specifically, when the program is executed, the control unit 111 functions as a changing unit 111a and a setting unit 111b. The changing unit 111a changes the first opening degree D1 which is the opening degree of the valve 16c and the second opening degree D2 which is the opening degree of the valve 16d based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd, so that the sum of the first opening degree D1 and the second opening degree D2 becomes a specified value Vp. The pressure rise of the primary refrigerant C1 in the joint 16a, the pipes 16e, 16f, and the valve 16c is suppressed.

[0050] Specifically, the valves 16c and 16d have the same specifications. In addition, the opening degrees of the valves 16c and 16d represent the ratio of the opening area of the valve seat to the total opening area at any moving amount of each valve body. The valve seat is a component that receives the valve body when the valve body is in the fully closed position.

[0051] In the embodiment, for ease of understanding, the opening degree is expressed as a percentage. In this case, the specified value Vp is approximately 100 [%] or more. As the specified value Vp, 100 [%] or 120 [%] is exemplified. If the specified value Vp is 100 [%] or more, it can be a fixed value or a variable value. In addition, as long as the pressure rise of the primary refrigerant C1 is suppressed, the specified value Pv can also be 100 [%] or less. For example, the specified value Pv can be 80 [%]. In order to prevent dew condensation in the heat exchanger 18, even if the changing unit 111a reduces the first opening degree D1, the second opening degree D2 will be increased, thus suppressing the pressure rise of the primary refrigerant C1 in the joint 16a, the pipes 16e, 16f, and the valve 16c.

[0052] In addition, a pressure relief valve is sometimes used in the fluid circuit. However, a general pressure relief valve only releases excessive pressure, so it is not suitable for the CDU1 that needs to prevent dew condensation. Therefore, in the embodiment, the CDU1 includes flow adjustable valves 16c and 16d, and the changing unit 111a changes the first opening degree D1 and the second opening degree D2 based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd, so that the sum of the first opening degree D1 and the second opening degree D2 becomes a specified value Vp.

[0053] The change unit 111a periodically determines the change amplitudes ΔD of the first opening degree D1 and the second opening degree D2 based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd, and then changes the first opening degree D1 and the second opening degree D2 by the change amplitude ΔD. The temperature of the secondary refrigerant C2 can be reduced in a relatively short time.

[0054] The setting unit 111b sets the target temperature Tt of the secondary temperature T2o. The change unit 111a changes the first opening degree D1 and the second opening degree D2 so that the secondary temperature T2o approaches the target temperature Tt. The cooling performance of the primary refrigerant C1 is maintained by the secondary refrigerant C2.

[0055] During the period when the target temperature Tt is below the dew point based on the device temperature Td and the relative humidity Hd, the change unit 111a changes the first opening degree D1 and the second opening degree D2 so that the secondary temperature T2o does not drop below the dew point. Thereby, the occurrence of condensation inside the CDU1 is suppressed.

[0056] Next, Figures 1 to 6 a more detailed process of the control unit 111 will be described.

[0057] As Figures 3 to 5 shown, the process of the control unit 111 includes steps S101 to S127.

[0058] In step S101, the control unit 111 causes the touch screen of the operation unit 110 to display an input screen. The input screen is a screen for the user of the CDU1 to input the target temperature Tt. The operation unit 110 sends information representing the target temperature Tt specified by the user operation (hereinafter also simply referred to as "target temperature Tt") to the control unit 111.

[0059] In step S102, the control unit 111 functions as the setting unit 111b. For example, the setting unit 111b sets the target temperature Tt received from the operation unit 110 in the memory.

[0060] In step S103, the control unit 111 operates the pumps 17c, 17d. At this time, the pump 65 also operates on the cooling device 6 side. The fluid and discharge amount of the pumps 17c, 17d, 65 are appropriately determined. As a result, the primary refrigerant C1 flows into the primary inlet 11. The primary refrigerant C1 flows through the primary flow path 16. The primary refrigerant C1 flows out from the primary outlet 12. The secondary refrigerant C2 flows into the secondary inlet 13. The secondary refrigerant C2 flows through the secondary flow path 17. The secondary refrigerant C2 flows out from the secondary outlet 14. The primary refrigerant C1 and the secondary refrigerant C2 become objects for heat exchange in the heat exchanger 18.

[0061] In steps S104 to S127, the control unit 111 functions as the change unit 111a.

[0062] In step S104, the changing unit 111a determines the first opening degree D1 as the first initial value D10, and determines the second opening degree D2 as the second initial value D20. The changing unit 111a changes the first opening degree D1 of the valve 16c to the first initial value D10, and changes the second opening degree D2 of the valve 16d to the second initial value D20.

[0063] Assume that after the CDU1 operates, the secondary temperature T2o immediately becomes a relatively high temperature. In order to relatively quickly reduce the secondary temperature T2o, the first initial value D10 and the second initial value D20 are set, for example, to satisfy the following conditions (a) and (b). Condition (a) is that the sum of the first initial value D10 and the second initial value D20 is a specified value Vp. Condition (b) is that the first initial value D10 is greater than the second initial value D20. By satisfying conditions (a) and (b), the low-temperature primary refrigerant C1 flows into the flow path 18e relatively early and in a large amount. Therefore, the changing unit 111a changes the first opening degree D1 and the second opening degree D2 so that the secondary temperature T2o approaches the target temperature Tt. Additionally, condition (b) is that the first initial value D10 is less than or equal to the second initial value D20.

[0064] In step S105, the changing unit 111a starts timing from the initial value t0 using a timer (not shown) provided inside the control unit 111.

[0065] In step S106, the changing unit 111a determines whether the timer has counted a specific time tp. If it is determined that the specific time tp has not been counted (in step S106, "no"), the process returns to step S106. If it is determined that the specific time tp has been counted (in step S106, "yes"), the process proceeds to step S107.

[0066] By repeating the processing cycle defined by steps S105 to S127, the changing unit 111a can periodically determine the change amplitude ΔD between the first opening degree D1 and the second opening degree D2 based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd, and then change the first opening degree D1 and the second opening degree D2 by the change amplitude ΔD.

[0067] In step S107, the changing unit 111a obtains the secondary temperature T2o, the device temperature Td, and the relative humidity Hd from the sensor unit 19. In step S107, the changing unit 111a also uses a known technique to obtain the dew point temperature DP based on the device temperature Td and the relative humidity Hd.

[0068] In step S108, the changing unit 111a determines whether the target temperature Tt is equal to or lower than the dew point temperature DP. If it is equal to or lower than the dew point temperature DP (Yes in step S108), the process proceeds to step S109. If it is not equal to or lower than the dew point temperature DP (No in step S108), the process proceeds to step S119.

[0069] In step S109, the changing unit 111a determines whether the secondary temperature T2o is equal to or lower than the dew point temperature DP. If it is determined that the secondary temperature T2o is equal to or lower than the dew point temperature DP (Yes in step S109), since condensation occurs around the heat exchanger 18, the process proceeds to step S110. If it is determined that the secondary temperature T2o is not equal to or lower than the dew point temperature DP (No in step S109), since no condensation occurs, the process proceeds to step S115 (see Figure 4 ).

[0070] In step S110, the changing unit 111a obtains the absolute value of the difference value between the secondary temperature T2o and the dew point temperature DP as the temperature difference ΔT1.

[0071] Next, in step S111, the changing unit 111a determines whether the temperature difference ΔT1 is equal to or greater than the reference value V1.

[0072] If it is determined that the temperature difference ΔT1 is equal to or greater than the reference value V1 (Yes in step S111), since the secondary temperature T2o is much lower than the dew point temperature DP, the process proceeds to step S112. When the conditions (c1), (d1), and (e1) shown within the dashed box W1 in Figure 6 are satisfied, step S112 is executed. The condition (c1) is that the target temperature Tt is equal to or lower than the dew point temperature DP (see step S108). The condition (d1) is that the secondary temperature T2o is equal to or lower than the dew point temperature DP (see step S109). The condition (e1) is that the temperature difference ΔT1 is equal to or greater than the reference value V1 (see step S111).

[0073] On the other hand, if it is determined that the temperature difference ΔT1 is not equal to or greater than the reference value V1 (No in step S111), since the secondary temperature T2o is near the dew point temperature DP, the process proceeds to step S113. When the conditions (c1), (d1), and (e2) shown within the dashed box W2 in Figure 6 are satisfied, step S113 is executed. The condition (e2) is that the temperature difference ΔT1 is less than the reference value V1 (see step S111).

[0074] In step S112, the changing unit 111a determines the change range ΔD as the change range ΔD1 (also see Figure 6of the frame W1). In the same step, the changing unit 111a further changes the first opening degree D1 to be smaller than the current opening degree by a change amplitude ΔD1. In addition, the changing unit 111a changes the second opening degree D2 to be larger than the current opening degree by the change amplitude ΔD1.

[0075] In addition, the sum of the first initial value D10 and the second initial value D20 is a specified value Vp. Even after executing step S112, the sum of the first opening degree D1 and the second opening degree D2 is also the specified value Vp. In addition, even after executing the subsequent steps S113, S117, S118, S126, and S127, the sum of the first opening degree D1 and the second opening degree D2 is also the specified value Vp.

[0076] In step S113, the changing unit 111a determines the change amplitude ΔD as the change amplitude ΔD2 (also refer to Figure 6 inside the frame W2). In the same step, the changing unit 111a further changes the first opening degree D1 to be smaller than the current opening degree by the change amplitude ΔD2. The changing unit 111a further changes the second opening degree D2 to be larger than the current opening degree by the change amplitude ΔD2.

[0077] The change amplitude ΔD2 is smaller than the change amplitude ΔD1. Therefore, when step S112 is executed, the flow rate of the primary refrigerant C1 in the flow path 18e is smaller than that when step S113 is executed. Therefore, when step S112 is executed, the secondary temperature T2o can be greatly increased, and thus dew condensation around the heat exchanger 18 can be suppressed as early as possible. On the other hand, when step S113 is executed, the secondary temperature T2o can be made slightly higher than the dew point temperature DP. Therefore, while suppressing dew condensation inside the CDU1, the heat source 5 is cooled well. When the target temperature Tt is below the dew point temperature DP, while the secondary temperature T2o is below the dew point temperature DP, the changing unit 111a executes steps S108 to S113. That is, the CDU1 does not set the secondary temperature T2o to the target temperature Tt, but changes the first opening degree D1 and the second opening degree D2 so that the secondary temperature T2o exceeds the dew point temperature DP as early as possible. Thereby, both the suppression of dew condensation inside the CDU1 and the cooling performance of the heat source 5 are taken into account.

[0079] After step S112 or step S113, in step S114, the changing unit 111a starts timing from the initial value t0 through a built-in timer (not shown). Thereafter, the process returns to step S106.

[0080] As Figure 4 shown, in step S115, the changing unit 111a obtains the temperature difference ΔT1 described in step S110 (refer to Figure 3 ).

[0081] Next, in step S116, the changing unit 111a determines whether the temperature difference ΔT1 is equal to or greater than the reference value V2.

[0082] In the case where it is determined to be equal to or greater than the reference value V1 (in step S116, "Yes"), since the secondary temperature T2o greatly exceeds the dew point temperature DP, the process proceeds to step S117. When the conditions (c1), (d2), and (f1) shown within the dashed box W3 in Figure 6 are satisfied, step S117 is executed. Condition (d2) is that the secondary temperature T2o exceeds the dew point temperature DP (refer to step S109). Condition (f1) is that the temperature difference ΔT1 is equal to or greater than the reference value V2 (refer to step S116).

[0083] On the other hand, in the case where it is determined not to be equal to or greater than the reference value V2 (in step S116, "No"), since the secondary temperature T2o is near the dew point temperature DP, the process proceeds to step S118. When the above conditions (c1), (d2), and condition (f2) shown within the dashed box W4 in Figure 6 are satisfied, step S118 is executed. Condition (f2) is that the temperature difference ΔT1 is less than the reference value V2 (refer to step S116).

[0084] In step S117, the changing unit 111a determines the change magnitude ΔD to be the change magnitude ΔD3 (also refer to within the box W3 in Figure 6 ). In the same step, the changing unit 111a further increases the first opening degree D1 by the change magnitude ΔD3 from the current opening degree. The changing unit 111a further decreases the second opening degree D2 by the change magnitude ΔD3 from the current opening degree.

[0085] In step S118, the changing unit 111a determines the change magnitude ΔD to be the change magnitude ΔD4 (also refer to within the box W4 in Figure 6 ). In the same step, the changing unit 111a further increases the first opening degree D1 by the change magnitude ΔD4 from the current opening degree. The changing unit 111a further decreases the second opening degree D2 by the change magnitude ΔD4 from the current opening degree.

[0086] Executing either step S117 or S118 will reduce the secondary temperature T2o. Among them, the change magnitude ΔD4 is less than the change magnitude ΔD3. Therefore, when step S117 is executed, the secondary temperature T2o approaches the dew point temperature DP relatively earlier. When step S118 is executed, the secondary temperature T2o remains near the dew point temperature DP.

[0087] After step S117 or step S118, the process proceeds to step S114 (refer to Figure 3 ). As in Figure 5As shown, in step S119, the changing unit 111a determines whether the secondary temperature T2o is equal to or higher than the target temperature Tt. If it is determined that the temperature is equal to or higher than the target temperature Tt (Yes in step S119), the process proceeds to step S120. If it is determined that the temperature is not equal to or higher than the target temperature Tt (No in step S119), the process proceeds to step S124.

[0089] In step S120, the changing unit 111a obtains the absolute value of the difference between the secondary temperature T2o and the target temperature Tt as the temperature difference ΔT2.

[0090] Next, in step S121, the changing unit 111a determines whether the temperature difference ΔT2 is equal to or higher than the reference value V3. If it is determined that the temperature difference is equal to or higher than the reference value V3 (Yes in step S121), since the secondary temperature T2o greatly exceeds the target temperature Tt, the process proceeds to step S122. When the conditions (c2), (f1), and (g1) shown within the dashed box W5 in Figure 6 are satisfied, step S122 is executed. Condition (c2) is that the target temperature Tt exceeds the dew point temperature DP (refer to step S108). Condition (f1) is that the secondary temperature T2o is equal to or higher than the target temperature Tt (refer to step S119). Condition (g1) is that the temperature difference ΔT2 is equal to or higher than the reference value V3 (refer to step S121).

[0091] On the other hand, if it is determined that the temperature difference is not equal to or higher than the reference value V3 (No in step S121), since the secondary temperature T2o is near the target temperature Tt, the process proceeds to step S123. When the above-mentioned conditions (c2), (f1), and condition (g2) shown within the dashed box W6 in Figure 6 are satisfied, step S123 is executed. Condition (g2) is that the temperature difference ΔT2 is less than the reference value V3 (refer to step S121).

[0092] In step S122, the changing unit 111a determines the change amplitude ΔD as the change amplitude ΔD5. In the same step, the changing unit 111a further increases the first opening degree D1 by the change amplitude ΔD5 from the current opening degree. The changing unit 111a further decreases the second opening degree D2 by the change amplitude ΔD5 from the current opening degree.

[0093] In step S123, the changing unit 111a determines the change amplitude ΔD as the change amplitude ΔD6. In the same step, the changing unit 111a further increases the first opening degree D1 by the change amplitude ΔD6 from the current opening degree. The changing unit 111a further decreases the second opening degree D2 by the change amplitude ΔD6 from the current opening degree.

[0094] Therefore, in steps S122 and S123, when the difference between the secondary temperature T2o and the dew point temperature DP based on the device temperature Td and the relative humidity Hd (i.e., the temperature difference Δ2) is equal to or greater than the reference value V3, the changing unit 111a determines the change amplitude ΔD of the first opening D1 and the second opening D2 as the change amplitude ΔD5, and then increases the first opening D1 by the change amplitude ΔD5 and decreases the second opening D2 by the change amplitude ΔD5 to make the temperature of the secondary refrigerant C2 approach the target temperature Tt. On the other hand, when the difference between the secondary temperature T2o and the dew point temperature DP based on the device temperature Td and the relative humidity Hd (i.e., the temperature difference Δ2) is less than the reference value V3, the changing unit 111a determines the change amplitude ΔD of the first opening D1 and the second opening D2 as the change amplitude ΔD6 that is less than the change amplitude ΔD5, and changes the first opening D1 and the second opening D2 by the change amplitude ΔD6. Thereby, the temperature of the secondary refrigerant C2 approaches the target temperature Tt in a short time and is not easily below the dew point.

[0095] The reference value V3 is an example of the "reference value" in the present disclosure. The change amplitude ΔD5 is an example of the "first change amplitude" in the present disclosure. The change amplitude ΔD6 is an example of the "second change amplitude" in the present disclosure.

[0096] Specifically, when any one of steps S122 and S123 is executed, the secondary temperature T2o will decrease. Among them, the change amplitude ΔD6 is less than the change amplitude ΔD5. Therefore, when step S122 is executed, the secondary temperature T2o approaches the target temperature Tt relatively early. When step S123 is executed, the secondary temperature T2o is maintained near the target temperature Tt. In addition, the secondary temperature T2o is not easily below the dew point temperature DP.

[0097] After step S122 or step S123, the process proceeds to step S114 (see Figure 3 ).

[0098] In step S124, the changing unit 111a calculates the temperature difference ΔT2 described in step S120.

[0099] Next, in step S125, the changing unit 111a determines whether the temperature difference ΔT2 is equal to or greater than the reference value V4.

[0100] In the case where it is determined to be equal to or greater than the reference value V4 (in step S125, "yes"), since the secondary temperature T2o is much lower than the target temperature Tt, the process proceeds to step S126. When the following conditions are met Figure 6When the above conditions (c2), (f2), and (h1) shown within the dashed-line box W7 in [reference] are satisfied, step S126 is executed. Condition (f2) is that the secondary temperature T2o is less than the target temperature Tt (refer to step S119). Condition (h1) is that the temperature difference ΔT2 is equal to or greater than the reference value V4 (refer to step S125).

[0101] On the other hand, when it is determined that the temperature difference ΔT2 is not equal to or greater than the reference value V4 (i.e., "No" in step S125), as the secondary temperature T2o is slightly lower than the target temperature Tt, the process proceeds to step S127. When the above conditions (c2), (f2), and (h2) shown within the dashed-line box W8 in [reference] are satisfied, step S127 is executed. Condition (h2) is that the temperature difference ΔT2 is less than the reference value V4 (refer to step S125). Figure 6 When the above conditions (c2), (f2), and (h2) shown within the dashed-line box W8 in [reference] are satisfied, step S127 is executed. Condition (h2) is that the temperature difference ΔT2 is less than the reference value V4 (refer to step S125).

[0102] In step S126, the changing unit 111a determines the changing range ΔD as the changing range ΔD7. In the same step, the changing unit 111a further decreases the first opening degree D1 from the current opening degree by the changing range ΔD7. The changing unit 111a further increases the second opening degree D2 from the current opening degree by the changing range ΔD7.

[0103] In step S127, the changing unit 111a determines the changing range ΔD as the changing range ΔD8. In the same step, the changing unit 111a further decreases the first opening degree D1 from the current opening degree by the changing range ΔD8. The changing unit 111a further increases the second opening degree D2 from the current opening degree by the changing range ΔD8.

[0104] When either step S126 or S127 is executed, the secondary temperature T2o increases. Among them, the changing range ΔD8 is less than the changing range ΔD7. Therefore, when step S126 is executed, the secondary temperature T2o approaches the target temperature Tt relatively earlier. When step S127 is executed, the secondary temperature T2o is maintained near the target temperature Tt.

[0105] After step S126 or step S127, the process proceeds to step S114 (refer to Figure 3 ).

[0106] [Modification Example 1] As shown in Figure 7 , in the CDU1, the sensor unit 19 further detects the primary temperature T1i, which is the temperature of the primary refrigerant C1, on the upstream side of the heat exchanger 18. Specifically, the sensor unit 19 further includes a temperature sensor 19d.

[0107] Specifically, the temperature sensor 19d detects the primary temperature T1i between the primary flow inlet 11 on the upstream side of the heat exchanger 18 in the primary flow path 16 and the inlet 18a, and outputs information representing the primary temperature T1i (hereinafter also simply referred to as "primary temperature T1i") to the control unit 111. The change unit 111a determines the period for changing the first opening degree D1 and the second opening degree D2 based on the primary temperature T1i, the device temperature Td, and the relative humidity Hd, and then periodically changes the first opening degree D1 and the second opening degree D2. Thereby, condensation is not likely to occur in the CDU1.

[0109] Specifically, as Figure 8 shown, the processing of the CDU1 of Modification 1, after executing any one of steps S112, S113, S117, S118, S122, S123, S126, S127, and before executing step S114, further includes steps S201 to S204.

[0110] In step S201, the change unit 111a acquires the primary temperature T1i from the sensor unit 19.

[0111] In step S202, the change unit 111a determines whether the primary temperature T1i obtained in step S201 is below the dew point temperature DP obtained in step S107. If it is determined that the temperature is below the dew point temperature DP (in step S202, "yes"), the process proceeds to step S203. On the other hand, if it is determined that the temperature is not below the dew point temperature DP (in step S202, "no"), the process proceeds to step S204.

[0112] In step S203, the change unit 111a updates the specific time tp used in step S106 to a specific time tp1.

[0113] In step S204, the change unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0114] According to Modification 1, when the primary temperature T1i is below the dew point temperature DP, the specific time tp is relatively shortened, so that the period for changing the first opening degree D1 and the second opening degree D2 becomes shorter. That is, the first opening degree D1 and the second opening degree D2 are changed frequently. Specifically, when the primary temperature T1i is below the dew point temperature DP, steps S112 and S113 can be frequently executed. Thereby, condensation is not likely to occur in the CDU1.

[0115] [Modification 2] The structure of the CDU1 of Modification 2 can be the same as that of the CDU1 of the embodiment (refer to Figure 2) are the same. Therefore, in Modification 2, reference is made to Figure 2 .

[0116] As Figure 2 shown, the sensor unit 19 detects the secondary temperature T2o on the downstream side of the heat exchanger 18 in the secondary flow path 17 (i.e., an example of the "third flow path").

[0117] The changing unit 111a determines the period for changing the first opening degree D1 and the second opening degree D2 based on at least one of the combination of the secondary temperature T2o, the device temperature Td, and the relative humidity Hd and the target temperature Tt, and then periodically changes the first opening degree D1 and the second opening degree D2. Thereby, dew condensation is not likely to occur in the CDU1, or the secondary refrigerant C2 reaches the target temperature Tt in a short time.

[0118] Specifically, as Figure 9 shown, the processing of the CDU1 in Modification 2 further includes steps S301 and S302 to replace steps S112 and S113 (refer to Figure 3 ).

[0119] In step S301, in addition to the processing described in step S112, the changing unit 111a updates the specific time tp used in step S106 to a specific time tp1.

[0120] In step S302, in addition to the processing described in step S113, the changing unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0121] As Figure 10 shown, the processing of the CDU1 in Modification 2 further includes steps S303 and S304 to replace steps S117 and S118 (refer to Figure 4 ).

[0122] In step S303, in addition to the processing described in step S117, the changing unit 111a updates the specific time tp used in step S106 to a specific time tp1.

[0123] In step S304, in addition to the processing described in step S118, the changing unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0124] According to Modification 2, when there is a large difference between the secondary temperature T2o and the dew point temperature DP, by making the specific time tp relatively short, the first opening degree D1 and the second opening degree D2 are changed frequently. Thereby, dew condensation is not likely to occur inside the CDU1.

[0125] As Figure 11As shown, the processing of the CDU1 in Modification 2 further includes steps S305, S306, S307, and S308 to replace steps S122, S123, S126, and S127 (refer to Figure 5 ).

[0126] In step S305, in addition to the processing described in step S122, the changing unit 111a updates the specific time tp used in step S106 to a specific time tp1.

[0127] In step S306, in addition to the processing described in step S123, the changing unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0128] In step S307, in addition to the processing described in step S126, the changing unit 111a updates the specific time tp used in step S106 to a specific time tp1.

[0129] In step S308, in addition to the processing described in step S127, the changing unit 111a updates the specific time tp to a specific time tp2 that is longer than the specific time tp1.

[0130] According to Modification 2, when there is a large difference between the secondary temperature T2o and the target temperature Tt, by making the specific time tp relatively short, the first opening degree D1 and the second opening degree D2 are changed frequently. Thus, the secondary temperature T2o approaches the target temperature Tt earlier.

[0131] [Modification 3] As Figure 12 shown, the CDU1 in Modification 3 includes a proportional control type electric three-way valve 112 to replace the joint 16a, valves 16c, 16d, and pipes 16f, 16h. With the electric three-way valve 112, the changing unit 111a can also change the position of the valve body 112a in the electric three-way valve 112, and change the first opening degree D1 and the second opening degree D2 in the same manner as in the embodiment.

[0132] In addition, for the convenience of understanding the present disclosure, the drawings mainly schematically show each component, and for the creation of the drawings, the thickness, length, number, interval, etc. of each shown component may be different from the actual ones. In addition, the structure of each component shown in the above embodiment is an example and is not particularly limited. Of course, various changes can be made within the range of not substantially departing from the effects of the present disclosure. The valve 16c adjusts the first flow rate F1. The first flow rate F1 is the flow rate of the primary refrigerant C1 in the flow path (i.e., the "first flow path" of the present disclosure) from the joint 16a via the valve 16c to the joint 16b. The valve 16d adjusts the second flow rate F2. The second flow rate F2 is the flow rate of the primary refrigerant C1 in the flow path (i.e., the "second flow path" of the present disclosure) from the joint 16a via the valve 16d to the joint 16b. The change unit 111a changes the first opening D1 which is the opening degree of the valve 16c and the second opening D2 which is the opening degree of the valve 16d based on the secondary temperature T2o, the device temperature Td, and the relative humidity Hd so that the sum of the first flow rate F1 and the second flow rate F2 becomes a specified value Vp2. Thereby, the pressure rise of the primary refrigerant C1 in the joint 16a, the pipes 16e, 16f, and the valve 16c is suppressed. In addition, in this case, the first flow rate F1 and the second flow rate F2 can be measured by the flow sensors provided in each of the pipes 16g, 16j. The change unit 111a can further change the first opening D1 and the second opening D2 so that the sum of the first flow rate F1 and the second flow rate F2 becomes the specified value Vp2.

[0134] In the embodiment, the control unit 111 is included in the CDU1. However, it is not limited thereto, and the control unit 111 can be provided in an external device different from the CDU1, such as the cooling device 6. In addition, the control unit 111 can be provided in an electronic device which is an example of the heat source 5. In this case, the control unit 111 controls each component of the structure of the CDU1 through communication.

[0135] In the embodiment, the first flow path and the second flow path converge at the joint 16b inside the housing 15. However, it is not limited thereto, and the first flow path and the second flow path can converge outside the housing 15.

[0136] In the embodiment, in Figures 3 to 5 the process, the specified value Pv is a fixed value. However, it is not limited thereto, and in step S107, the change unit 111a can determine the specified value Pv based on the dew point temperature DP obtained in this step. Specifically, the lower the dew point temperature DP, the smaller the specified value Pv is determined. Thereby, the condensation inside the CDU1 is suppressed, and the pressure rise in the primary flow path 16 of the primary refrigerant C1 is suppressed.

[0137] In addition, in Figure 3 step S109 when it is determined that the secondary temperature T2o is below the dew point temperature DP (when it is "yes" in step S109), the specified value Pv can be decreased. Thereby, the condensation inside the CDU1 is suppressed, and the pressure rise in the primary flow path 16 of the primary refrigerant C1 is suppressed. In addition, the present technology can also adopt the following structure.

[0139] (1) A refrigerant cycle device, comprising: a common flow path through which a primary refrigerant flows; A first flow path and a second flow path branched from the common flow path; A third flow path through which a secondary refrigerant flows; A heat exchanger, wherein the first flow path and the third flow path pass through the interior of the heat exchanger to effect heat exchange between the primary refrigerant and the secondary refrigerant; A first valve that adjusts the flow rate of the primary refrigerant in the first flow path; A second valve that adjusts the flow rate of the primary refrigerant in the second flow path; A sensor unit that detects a secondary temperature as the temperature of the secondary refrigerant, a device temperature as the temperature inside the device, and the relative humidity inside the device; and A change unit that changes a first opening degree as the opening degree of the first valve and a second opening degree as the opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity, such that the sum of the first opening degree and the second opening degree becomes a specified value.

[0140] (2) The refrigerant cycle device according to (1), wherein the change unit periodically determines a change amplitude of the first opening degree and the second opening degree based on the secondary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree by the change amplitude.

[0141] (3) The refrigerant cycle device according to (1) or (2), further comprising a setting unit that sets a target temperature of the secondary temperature, The change unit changes the first opening degree and the second opening degree such that the secondary temperature approaches the target temperature.

[0142] (4) The refrigerant cycle device according to (3), wherein during a period when the target temperature is below the dew point based on the device temperature and the relative humidity, the change unit changes the first opening degree and the second opening degree such that the secondary temperature does not reach below the dew point. (5) The refrigerant cycle device according to any one of (1) to (4), wherein the sensor unit further detects a primary temperature as the temperature of the primary refrigerant on the upstream side of the heat exchanger, The change unit determines a cycle for changing the first opening degree and the second opening degree based on the primary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree according to the cycle.

[0144] (6) The refrigerant cycle device according to (3), wherein the sensor unit is on the downstream side of the heat exchanger in the third flow path and detects the secondary temperature. The changing unit determines a period for changing the first opening degree and the second opening degree based on at least one of a combination of the secondary temperature, the device temperature, and the relative humidity and the target temperature, and then changes the first opening degree and the second opening degree according to the period.

[0145] (7) The refrigerant cycle device according to any one of (1) to (6), wherein the first valve is a two-way valve provided in the first flow path. The second valve is a two-way valve provided in the second flow path. The flow rates of the first flow path and the second flow path are the same as each other.

[0146] (8) The refrigerant cycle device according to any one of (1) to (7), wherein the changing unit includes an electronic circuit and is located above the common flow path, the first flow path, the second flow path, and the third flow path in the vertical direction of the device.

[0147] (9) The refrigerant cycle device according to (3), wherein in the changing unit, when the difference between the secondary temperature and the dew point based on the device temperature and the relative humidity is equal to or greater than a reference value, the changing amplitude of the first opening degree and the second opening degree is determined as a first changing amplitude, and then the first opening degree is increased according to the first changing amplitude, and the second opening degree is decreased according to the first changing amplitude so that the temperature of the secondary refrigerant approaches the target temperature. when the difference between the secondary temperature and the dew point is less than the reference value, the changing amplitude of the first opening degree and the second opening degree is determined as a second changing amplitude smaller than the first changing amplitude, and the first opening degree and the second opening degree are changed with the second changing amplitude.

[0148] (10) The refrigerant cycle device according to any one of (1) to (9), wherein the changing unit changes the specified value based on the secondary temperature, the device temperature, and the relative humidity.

[0149] (11) The refrigerant cycle device according to any one of (1) to (10), wherein when the secondary temperature is below the dew point, the changing unit decreases the specified value.

[0150] (12) A refrigerant cycle device, comprising: a common flow path through which a primary refrigerant flows; a first flow path and a second flow path branched from the common flow path; A third flow path through which a secondary refrigerant flows; A heat exchanger through which the first flow path and the third flow path pass inside, for heat exchange between the primary refrigerant and the secondary refrigerant; A first valve that adjusts the flow rate of the primary refrigerant in the first flow path, i.e., the first flow rate; A second valve that adjusts the flow rate of the primary refrigerant in the second flow path, i.e., the second flow rate; A sensor unit that detects a secondary temperature as the temperature of the secondary refrigerant, a device temperature as the temperature inside the device, and the relative humidity inside the device; and An alteration unit that changes a first opening degree as the opening degree of the first valve and a second opening degree as the opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity, such that the sum of the first flow rate and the second flow rate becomes a specified value.

[0151] (13) A control method, which is a control method for a refrigerant cycle device, the refrigerant cycle device including: A common flow path through which a primary refrigerant flows; A first flow path and a second flow path branched from the common flow path; A third flow path through which a secondary refrigerant flows; A heat exchanger through which the first flow path and the third flow path pass inside, for heat exchange between the primary refrigerant and the secondary refrigerant; A first valve that adjusts the flow rate of the primary refrigerant in the first flow path; A second valve that adjusts the flow rate of the primary refrigerant in the second flow path, wherein, The secondary temperature as the temperature of the secondary refrigerant, the device temperature as the temperature inside the device, and the relative humidity inside the device are detected, Based on the secondary temperature, the device temperature, and the relative humidity, the first opening degree as the opening degree of the first valve and the second opening degree as the opening degree of the second valve are changed such that the sum of the first opening degree and the second opening degree becomes a specified value. Industrial applicability

[0152] The refrigerant cycle device and the control method of the present disclosure have industrial applicability. Reference numeral description

[0153] 1: Refrigerant cycle device, 16: Primary flow path, 16e: Pipe (common flow path), 16a, 16b: Joints (first flow path, second flow path) 16f, 16g, 16j: Tubes (first flow path), 16c: Valve (first flow path, first valve), 16h, 16i: Tubes (second flow path), 16d: Valve (second flow path, second valve), 17: Secondary flow path (third flow path), 18: Heat exchanger, 18e: Flow path (first flow path), 19: Sensor section, 111: Control section, 111a: Changing section, 111b: Setting section.

Claims

1. A refrigerant cycle device, characterized in that, Comprising: A common flow path through which a primary refrigerant flows; A first flow path and a second flow path branching from the common flow path; A third flow path through which a secondary refrigerant flows; A heat exchanger, wherein the first flow path and the third flow path pass through the interior of the heat exchanger, and the heat exchanger exchanges heat between the primary refrigerant and the secondary refrigerant; A first valve that adjusts the flow rate of the primary refrigerant in the first flow path; A second valve that adjusts the flow rate of the primary refrigerant in the second flow path; A sensor unit that detects a secondary temperature as the temperature of the secondary refrigerant, a device temperature as the temperature inside the device, and the relative humidity inside the device; And A changing unit that, based on the secondary temperature, the device temperature, and the relative humidity, changes a first opening degree as the opening degree of the first valve and a second opening degree as the opening degree of the second valve such that the sum of the first opening degree and the second opening degree becomes a specified value.

2. The refrigerant cycle device according to claim 1, wherein The changing unit periodically determines a change amplitude of the first opening degree and the second opening degree based on the secondary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree by the change amplitude.

3. The refrigerant cycle device according to claim 1 or 2, wherein It further includes a setting unit that sets a target temperature of the secondary temperature, The changing unit changes the first opening degree and the second opening degree such that the secondary temperature approaches the target temperature.

4. The refrigerant cycle device according to claim 3, wherein During a period when the target temperature is below the dew point based on the device temperature and the relative humidity, the changing unit changes the first opening degree and the second opening degree such that the secondary temperature does not fall below the dew point.

5. The refrigerant cycle device according to claim 1 or 2, wherein The sensor unit also detects a primary temperature as the temperature of the primary refrigerant on the upstream side of the heat exchanger, The changing unit determines a cycle for changing the first opening degree and the second opening degree based on the primary temperature, the device temperature, and the relative humidity, and then changes the first opening degree and the second opening degree according to the cycle.

6. The refrigerant cycle device according to claim 3, wherein The sensor unit detects the secondary temperature on the downstream side of the heat exchanger in the third flow path, The changing unit determines a cycle for changing the first opening degree and the second opening degree based on at least one of a combination of the secondary temperature, the device temperature, and the relative humidity and the target temperature, and then changes the first opening degree and the second opening degree according to the cycle.

7. The refrigerant cycle device according to claim 1 or 2, wherein The first valve is a two-way valve provided in the first flow path, The second valve is a two-way valve provided in the second flow path, The flow rates of the first flow path and the second flow path are the same as each other.

8. The refrigerant cycle device according to claim 1 or 2, characterized in that The changing unit includes an electronic circuit and is located above the common flow path, the first flow path, the second flow path, and the third flow path in the vertical direction of the device.

9. The refrigerant cycle device according to claim 3, characterized in that When the difference between the secondary temperature and the dew point based on the device temperature and the relative humidity is equal to or greater than a reference value, the changing unit determines the change amplitudes of the first opening degree and the second opening degree as a first change amplitude, then increases the first opening degree by the first change amplitude, and decreases the second opening degree by the first change amplitude so that the temperature of the secondary refrigerant approaches the target temperature. When the difference between the secondary temperature and the dew point is less than the reference value, the changing unit determines the change amplitudes of the first opening degree and the second opening degree as a second change amplitude smaller than the first change amplitude, and changes the first opening degree and the second opening degree by the second change amplitude.

10. The refrigerant cycle device according to claim 1 or 2, characterized in that The changing unit changes the specified value based on the secondary temperature, the device temperature, and the relative humidity.

11. The refrigerant cycle device according to claim 1 or 2, characterized in that When the secondary temperature is below the dew point, the changing unit decreases the specified value.

12. A refrigerant cycle device, characterized in that, Comprising: A common flow path through which a primary refrigerant flows; A first flow path and a second flow path branching from the common flow path; A third flow path through which a secondary refrigerant flows; A heat exchanger, the first flow path and the third flow path passing through the interior of the heat exchanger, and the heat exchanger performing heat exchange between the primary refrigerant and the secondary refrigerant; A first valve that adjusts the flow rate of the primary refrigerant in the first flow path, i.e., the first flow rate; A second valve that adjusts the flow rate of the primary refrigerant in the second flow path, i.e., the second flow rate; A sensor unit that detects a secondary temperature as the temperature of the secondary refrigerant, a device temperature as the temperature inside the device, and the relative humidity inside the device; And A changing unit that changes a first opening degree as the opening degree of the first valve and a second opening degree as the opening degree of the second valve based on the secondary temperature, the device temperature, and the relative humidity so that the sum of the first flow rate and the second flow rate becomes a specified value.

13. A control method, which is a control method of a refrigerant cycle device, the refrigerant cycle device comprising: A common flow path through which a primary refrigerant flows; A first flow path and a second flow path branching from the common flow path; A third flow path through which a secondary refrigerant flows; A heat exchanger, the first flow path and the third flow path passing through the interior of the heat exchanger, and the heat exchanger performing heat exchange between the primary refrigerant and the secondary refrigerant; A first valve that adjusts the flow rate of the primary refrigerant in the first flow path; and a second valve that adjusts the flow rate of the primary refrigerant in the second flow path, The control method is characterized in that a secondary temperature as the temperature of the secondary refrigerant, a device temperature as the temperature inside the device, and the relative humidity inside the device are detected, based on the secondary temperature, the device temperature, and the relative humidity, a first opening degree as the opening degree of the first valve and a second opening degree as the opening degree of the second valve are changed so that the sum of the first opening degree and the second opening degree becomes a specified value.

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